1. Field of the Invention
The present invention relates to a logic element. More particularly, the present invention relates to an integrated circuit or a field programmable gate array that includes such a logic element.
2. Description of Related Art
Complementary logic elements such as CMOS (Complementary metal-oxide-semiconductor) elements are of great importance for integrated circuits. CMOS technology is used in chips such as microprocessors, microcontrollers, static RAM, other digital logic circuits and camera devices. Two important characteristics of CMOS devices are high noise immunity and low static power supply drain. Significant power is only drawn when its transistors are switching between on- and off-states. The logic state of the CMOS is volatile and the input voltage has therefore to be maintained. However, due to gate leakage, static power consumption is increasing with increasing miniaturization. The need to maintain input voltage will lead to considerable power consumption and heating in future CMOS generations.
Another class of logic elements is the programmable logic device or PLD. Unlike a logic gate based on CMOS, which has a fixed function, a PLD has an undefined function at the time of manufacture. Before the PLD can be used in a circuit it must be programmed. A PLD can be considered as a combination of a logic device and a memory device. Antifuse devices, EEPROMs, solid-electrolyte switches or phase-change memories are used as memory devices or switches. PLDs such as FPGAs (field-programmable gate arrays) have more flexibility than fixed logic gates, can be re-programmed to fix errors and have a shorter time-to-market. However, FPGAs are generally slower than their application-specific integrated circuit (ASIC) counterparts, draw more power and are less area-efficient due to the combination of logic and memory elements.